Air quality sampler

ABSTRACT

A gas sampler is described for automatically collecting a plurality of different samples of a gas, such as from the atmosphere, at different time intervals. Such sampler includes a plurality of containers and associated pumps for collecting and retaining the samples. It further includes programmable control instrumentation for governing when a gas sample is collected into each of the containers. Each pump provides an average flow rate into its associated container by periodically starting and stopping operation during such period.

United States Patent [191 Newcomb, Jr. et al.

[4 Nov. 25, 1975 AIR QUALITY SAMPLER [75] Inventors: Gilbert S. Newcomb,Jr., Los Altos; Leon V. Langan, Jr., San Francisco, both of Calif.

[73] Assignee: Environmental Measurements, Inc.,

San Francisco, Calif.

[22] Filed: Jan. 14,1974

[21] Appl. No.: 433,273

[52] U.S. Cl 73/421.5 R [51] Int. Cl. ..G01N l/24 [58] Field of Search55/DIG. 41; 73/28, 170 R, 73/421.5 R, 422 GC, 422 R, 422 TC;

[56] References Cited UNITED STATES PATENTS 2,452,143 10/1948 Pellettere73/421.5 R 2,693,114 11/1954 Tapp et a1... 73/422 TC 3,299,700 1/1967Stout, Jr. 73/28 X 3,351,785 11/1967 Craig et a1... 239/70 X 3,440,4344/1969 Yates et a1 239/70 X 3,540,261 11/1970 Scoggins 73/42l.5 R3,765,247 10/1973 Riggs 73/421.5 R 3,815,354 6/1974 Strocka et a1 307/38X FOREIGN PATENTS OR APPLICATIONS 1,586,204 2/1970 France 73/42l.5

OTHER PUBLICATIONS Lourence, F. J. and W. O. Pruitt; Flexible BagsCollect Gas Samples; in Control Engineering; Sept, 1967; p. 105.

Primary Examiner-Richard C. Queisser Assistant Examiner-John S. ApplemanAttorney, Agent, or Firm-C. Michael Zimmerman, Esq.

[57] ABSTRACT A gas sampler is described for automatically collecting aplurality of different samples of a gas, such as from the atmosphere, atdifferent time intervals. Such sampler includes a plurality ofcontainers and associated pumps for collecting and retaining thesamples. It further includes programmable control instrumentation forgoverning when a gas sample is collected into each of the containers.Each pump provides an average flow rate into its associated container byperiodically starting and stopping operation during such period.

10 Claims, 5 Drawing Figures Patent Nov. 25, 1975 Sheet 1 0f 3 Sheet 2of 3 3,921,456

US. Patent Nov. 25, 1975 AIR QUALITY SAMPLER BACKGROUND OF THE INVENTIONThe present invention relates to monitoring a gas atmosphere and, moreparticularly, to a gas sampler which is programmable to automaticallycollect into individual containers, given quantities of an atmosphere atdifferent time intervals.

In the study and handling of air pollution, it is often desirable todetermine the character and concentration of pollutants at any givenlocation at different times. For example, in studying pollutiongenerated by automobiles in the vicinity of a highway or freeway, acomparison between traffic density and the resulting pollution is oftenimportant. Making such a comparison requires numerous measurements to betaken adjacent to the roadway at different times. Moreover, it is oftendesirable to determine whether or not pollutants from a known pollutionsources are reaching a given location and, if they are reaching thelocation, when and in what concentration.

In order to obtain pollution measurements at differing times at aspecific location, it has generally been necessary for personnel to beat the location at such times, and either make the measurement directlyat the site or obtain a sample of the atmosphere at such site for lateranalysis in a laboratory. Neither of these procedures, however, isentirely satisfactory. The necessity for personnel to be at the site atthe time of measurement not only adds to the expense, but reduces as apractical matter the number of differing sites which can be serviced inany given time period. In addition, onsite air pollution measurementapparatus is generally quite sophisticated and expensive.

SUMMARY OF THE INVENTION The present invention is a simple andinexpensive air quality sampler which enables a plurality of samples tobe automatically obtained from a given location at differing selectedtimes. In its basic aspects, the apparatus simply includes a pluralityof sample containers, such as inflatable, gas-impermeable bags, andpumping means for directing a quantity of the gas to be sampled intoeach of the containers. It further includes control instrumentationconnectable with such pumping means for governing when the pumping meansdirects the gas sample into any one of the containers. With thisarrangement, it will be recognized that with appropriate programming ofthe control instrumentation, samples of the atmosphere at the locationof the apparatus can be collected at differing times and segregated forlater analysis, merely by keeping track of which container receives asample at any given time. Numerous samples can thus be taken at a remotelocation without the necessity of personnel being available during thesampling.

Most desirably, the control instrumentation includes programming meanswhich permits an operator to change the time interval during which thepumping means directs a gas sample into each of the containers. Thearrangement then enables an operator to tailor the apparatus to obtainair samples at any given site at those times deememd to be of mostinterest. Moreover the pumping means preferably includes a plurality ofpumps, the output of each of which is connected with an associated oneof the containers. The inclusion of a separate pump for each of thecontainers obviates the need for a complex valving and air plumbingarrangement and the necessary sophisticated control therefor.

with such control means is activated. Most effectively.

such flow rate selection means varies the flow rate of the pump not byincreasing or decreasing the operating pumping rate of the pump, but byperiodically stopping and starting the operation of the pump during thefull time interval when it is activated to take a sample The resultingintermittent operation of the pump during the selected time intervalprovides the desired average flow rate, while also collecting gas fromthe atmosphere at times during the full time interval so that theresulting sample is an integration of the gas make-up during such fulltime interval. Intermittent operation of a pump to obtain a desired flowrate also eliminates the need for special (and more expensive) pumpshaving variable pumping speeds, besides resulting in a power savingadvantage. That is, because the average power consumed BRIEF DESCRIPTIONOF THE DRAWINGS With reference to the accompanying three sheets ofdrawings:

FIG. 1 is a partly broken-away, elevation view of a preferred embodimentof the air quality sampler of the invention;

FIG. 2 is an enlarged cross-sectional view of the top of the sampler ofFIG. 1, illustrating the mechanism and instrumentation therefor;

FIG. 3 is a further enlarged view showing details of one of the pumps ofthe apparatus and its relationship to other components of the airsampler;

FIG. 4 is an enlarged top plan view of the cover on said air sampler,and

FIG. 5 is a schematic diagram of the control instrumentation for the airsampler and its relationship to other mechanisms thereof.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT With reference first toFIG. 1, a stand-alone air quality sampler of the invention is generallyreferred to by the reference numeral 11. As is illustrated, such airquality sampler includes a protective enclosure 12 for housing collectedsamples of a gas, and an upper or cover portion 13 for the enclosurewhich also inclludes the operating mechanism for obtaining the gassamples. The protective enclosure is, as is illustrated, simply in theform of a barrel or similar housing. Most desirably, such enclosure isportable to enable the air sampler to be simply moved to any location atwhich it is desired to obtain samples-pm this connection, the enclosureis desirably of a plastic or other lightweight chemically inertmaterial. The capacity of the enclosure is dependent upon the desiredtotal volume of gas it is desired to sample in any given intended use.For example, a barrel having a two foot diameter and three foot heightwill adequately contain and protect 24. S-Iiter samples.

Each of the obtained samples is trapped within a container uniquelyasociated therewith which segregates it from other samples. The gascontainers are most simply gas impermeable bags 14 which are provided ina flat condition but which are inflatable by a gas sample as it istaken. It will be recognized. though. that other types of containers.such as liquid filled gas bubblers often used in the art. would alsosuffice.

Pumping means are provided for directing a sample quantity of the gas tobe analyzed into each of the bags 14 when desired. More particularly.each of the bags is communicated via a flexible hose 16 with a nipple 17extending through a bulk head 18 of the enclosure cover 13. A secondflexible hose l9 communicates the upper end of each of the nipples withthe flow output port 21 of a small piston pump 22 which is suitablymounted via bracket 23, for example. to the upper side of the bulk head.Associated with each of the pumps 22 is a simple. low operating power.dc driving motor 24.

Fromthe above. it will be seen that a separate pump 22 and a drivingmotor 24 therefor is associated with each of the sample bags. Thus. atany time it is desired to obtain a sample within a particular bag. it isnecessary to cause operation of the pump which is in communication withsuch bag. Although this provision of a plurality of pumps is amultiplication of similar parts. it has been found that the advantagesgained by such a redundancy far outweighs the additional costs whichmight be involved. One ofthe primary advantages is the elimination ofthe need for complex and sophisticated valving and control mechanismswhich would be required for appropriately divering gas to be sampledinto the various containers if only one pump were provided. Moreover. aspreviously discussed. the utilization of a plurality of simple pumpsresults in both a significant power saving and an extended operatinglife for the system.

As illustrated. the pumps 22 are circumferentially mounted on thebulkhead l8 inwardly of the latters outer circumference. The volumewithin which such pumps are located is separated from the externalenvironment by a cylindrical particulate filter 26. The purpose of suchfilter is to prevent larger particles within the atmosphere fromentering into the chamber of the pumps and fouling the same. An uppercover 27 is also provided having a downwardly extending peripheral skirt28 to provide protection for the filter 26 from the elements.

The air sampler further includes control means for governing when eachof the pumps directs a gas sample into its associated container. As canbe seen from FIGS. 2 and 4, such control means. generally referred to bythe reference numeral 29, is mounted on the underneath side of thebulkhead l8 centrally thereof. A suitable container 31 for a batterypower source is also mounted to the underneath side of the bulkheadadjacent the control mechanism.

The control means is adapted to activate each of the pumps 22 during adiscrete time interval selected especially for such pump and. hence. forfilling of the container associated therewith. For a detaileddescription of the control means. reference is made to FIG. 5 which is aschematic logic and electrical diagram of the instrumentation thereofand its relationship to the pumps. The pumps are represented in suchfigure at 22 and are shown connected to gas containers 14 by hoses 16.The power input to each of the pumps is provided by a pump driver 30which is energized by an output terminal 32 of an associated gate 33.Energization of the inputs to each gate 33 in a manner to be describedwill result in the operation of its associated pump 22'.

As a particularly salient feature of the instant invention. the controlinstrumentation includes programming means. generally referred to by thereference numeral 34. which permits the selected time interval duringwhich each of the pumps operates to be programmed or changed whendesired. In this connection, the programming means include a second setof gates 36 whose output terminals 37 provide. in effect, control outputconnections for the programming means. That is. each of such controloutput terminals 37 is associated with a discrete time interval and, inthis connection. is energized during such time interval by other aspectsof the control means. The number of gates 36 and. hence. control outputterminals 37 are dependent upon the number of time intervals that it isdesired to be able to utilize during any one cycle of operation of thesystem. In this particular embodiment in which hour long samples are tobe taken. 24 gates 36 and thus 24 different time intervals are provided,representing the 24 hours within a day. That is. each of the outputconnections is energized for a one-hour period during a day with eachrepresenting a particular one of the daily hours during which it mightbe desired to collect gas samples.

In order to provide proper. sequential energization of the outputconnections 37, the control instrumentation includes timing means,generally referred to by the reference numeral 38, for generating anoutput representative of the passage of time, and a time decoding means.generally referred to by the reference numeral 39 for receiving suchoutput and sequentially activating the output connections during thetime intervals represented thereby.

The timing means first includes an oscillator and divider 41, whichprovides a 60 hertz signal output. Such oscillator is. for example. astandard collector-base crystal feedback transistor oscillator, and thedivider a conventional binary divider. The 60 hertz signal output of theoscillator and divider is fed to a timing processor 42. Such processorprocesses the 60 hertz signal into a plurality of time divisionmultiplexed, time related outputs represented by flow line 43 which canbe decoded with synhronous timing to appropriately drive a time display44. The time display is, for example, a light emitting diode device offour digits representing hour and minute time divisions, the inputs ofwhich are appropriately connected to the timing processor time relatedoutputs.

The timing processor 42 also processes the 60 hertz input signal intobinary coded decimal (bcd) outputs representing the passage of hours andminutes. As represented by flow line 48, the bcd outputs of theprocessor are connected to a memory 46 which stores the timerepresentation of such output. The timing processor also directs strobepulses to the memory 46 as represented by the flow line 45 synchronouswith such timing pulses to cause storing in the memory of only thatportion of the bcd output of the timing processor representative of thehour at any given time. Most simply, the memory is in the form of twofour-element memories, one for storing the units of hour in bed formatand the other for storing the tens of hours in bed format.

The timing means further includes time setting means for synchronizingits operation with an external time source. That is, time setting inputsto the timing processor for hours and minutes are appropriatelyconnected through setting switches 49 to ground, to permit ad vancementof the outputs of the timing processor as necessary to synchronize thesame with an external time source, such as a watch showing the actualtime of day. The bed output of the timing processor 42 and, hence, theoutput of the timing means is then representative of the time of day aswell as the passage of time.

The time of day memory 46 output is fed to the time decoding means forappropriate decoding thereof and sequential activation of the controloutput connections so that each will be activated during a particularhour associated therewith during any 24 hour cycle. More particularly,the bed output of the memory representing hour units is fed to a unittime decoder 51 which converts the same to the unit decimal equivalentand a corresponding energization of the appropriate one of the tenoutput terminals 52 representing the decimal equivalent of the binaryinput from the memory 46.

The bed output of the memory representing the tens units in the decimalsystem is fed to a tens decoder 53 which provides the decimal equivalentthereof at its outputs 54. Since the particular embodiment being described is designed to provide a twenty-four hour cycle, the tens unitwill only vary from zero to two. This is the reason for only threeoutputs from the tens decoder rather than a full set of ten.

The output from the units and tens decoder are appropriately connectedwith the input terminals of the dual input gates 36 for sequentiallyactivating the output connections 37 as described above. Moreparticularly, the inputs to each of the gates represents the dig its ofthe hour associated therewith. That is, one of the inputs of the firstten gates 36 (only five of which are shown) is connected to the firstdecade output as shown, and the other input of each of such gates isconnected to the appropriate one of the unit time decoder outputs 52.This latter connection is represented in the drawing by a numbering ofthe gate inputs corresponding to a numbering of the unit time decoderoutputs. Similarly, one of the inputs to the gates representing thehours through I9 is connected to the second decade tens output of thedecoder 54, and the other input to each is connected with theappropriate unit time decoder. Because the particular unit beingdescribed is designed for twentyfour hour cycles, only four gates 36 areshown with one of their inputs connected to the third decade output 54of the decoder 53 and their other input appropriately connected to thefirst four unit time decoder outputs 52.

Simultaneous energization of both input terminals to any one gate willresult in energization of that gate output. Thus, as will be recognizedfrom the above, upon the decoding means providing an appropriate unitand tens output for each hour stored in the time of day memory, theproper control output connection will be energized. Thus, connectionwith a patch cord or the like between a control output connection 37representing a particular hour and an input terminals 55 to a gate 33associated with a chosen one of the containers 14 will result in suchinput terminal being energized.

The control instrumentation of the invention further includes time cyclecontrol means which allows both remote start-up and samples to be takenat different times within sequential twenty-four hour periods withoutthe necessity of an operator programming the same between cycles. Suchcontrol means is represented in the diagram by logic block 56. Asillustrated. such logic includes start cycle" logic in which an inputthereto on 57 will result in an output on. line 58 to enable mode logicrepresented at 47 which will respond thereto by applying an enablingsignal to the unit time decoder 51 as represented by flow line 60. Thatis, until such time as the start cycle logic is energized, the outputfrom the time of day memory 46 is not decoded by the unit time decoder.with the result that subsequent operation of the control unit dependentthereon is not initiated. and the output connections 37 cannot beenergized. Thus, the start of the cycle of operation of the pumps iscontrolled by the enable mode logic. Such enable logic is desirablyadapted to be energized by way of the start cycle logic either manuallyvia switch 65 or remotely through input 57. The completion of operationof a similar, adjacent air quality sampler can provide the energizationsignal through the input 57 if, for example, it is desired tosequentially operate several air quality samplers at a single location.

The cycle timer logic further includes means for controlling a specificpumps operation during a plurality of 24 hours cycles. That is, thecycle timer receives input as indicated by the input terminal from apatch cord connection to one of the output connections 37,representative of the beginning of the 24 hour cycle which the apparatusis starting at any particular time. The number of the cycle can beobtained by counting the number of times the chosen output connection 37has indicated a particular hour.

The cycle timer responds to an indication that the apparatus isundergoing the start of a particular cycle by energizing one of theoutput terminals 59 representative of the particular cycle. Thisenergization can be transferred with patch cords or the like to theinput 79 of each gate desired to operate during any particular cycle. Inthis connection, appropriate patch cords are used which allow stackingso that it is possible to have the input 79 to a plurality of the gates33 simultaneously connected to one of the cycle timer outputs 59 so thatmore than one pump 22 can be operated during any particular cycle.

The cycle timer further includes logic for cutting off power to thepumps and portions of the control apparatus both when a chosen cycle iscompleted and prior to application of an enabling signal to the startcycle logic. as Well as to provide an output signal to initiateoperation of another air quality sampler if desired. More particularly,the cycle timcr also includes cycle complete logic which is programmableto be energized at a chosen time during operation of the control system.Such cycle complete logic includes an input 61 which can be connectedwith a desired one of the cycle titncr outputs 59 to indicate the cycleduring which it is desired that the operation be terminated. A secondinput terminal 62 to the cycle complete logic is connectable with a pathcord or the like to a selected one of the output connections 37representing the time during a particular cycle at which it is desiredthat the operation be terminated. Upon simultaneous energization of bothof the inputs 61 and 62. the cycle complete logic puts out an outputsignal which is directed via line 63 to a switch 64 which is connectedto the power source represented at 66 for terminating its application ofpower to the pumps and a portion of the control circuity upon suchinitiation. By this means the power consumption of the system, when notrequired to operate, is minimized. As illustrated, a manual switch 67 isalso provided to enable an operator to manually control the operation ofthe system.

When power is initially applied to the system by closisng switch'67, thecycle timer logic 56 automatically assumes the cycle complete mode.Power is then applied only to the timing means 38 for time setting andmonitoring at display 44. It is only when the start cycle logic isenergized that the output signal on line 63 is re moved and power isapplied to the full system. allowing normal operation to start with thebeginning of the first 24 hour cycle as chosen by input to the 24 hourcycle time at terminal 80.

The output from the cycle complete logic also energizes an outputconnection 68. Such output connection can be connected, for example, tothe start cycle input 57 of the logic of another air quality sample toinitiate the latters standby mode logic and hence its cycling operation.

The control instrumention further includes flow rate selection means fordetermining the rate of flow of gas into each respective one of thecontainers during the time interval within which its associated pump isactivated. As previously mentioned, such flow rate selection meansprovides the desired average flow rate over the time it is desired topump a sample into a particular container by intermittently operatingthe pump, rather than varying the operating rate of such pump. The flowrate selection means is represented in the diagram at 71 and includes asample timer 72 providing intermittent energization on an output line73. As illustrated, the output of the sample timer is connected with thethird input 74 of each of the gates 33. Moreover, a multiposithat switch75 is provided for selectively connecting into the sample timer 72,differing delay components represented at 76, 77 and 78. Such delaycomponents affect the timer logic 72 by changing the ON/OFF timerelationships at the timer output. It will be recognized that byselecting which of the delay components 7678 is connected with the timer72, the rate at which the input 74 of each of the gates isintermittently energized can be changed.

Each of the tri-input gates 33 will only provide an output and operateits associated pump when all three of its inputs are energized. That is,the gas to be sampled will be directed into a container only when itsassociated gate is programmed by suitable connections with the outputconnection 37 and the cycle connections 59 to do so. Furthermore,because of the flow rate selection connection to the input 74 of each ofthe gates, such gate will cause intermittent operation of the pumpduring such time to obtain an average flow rate.

From the above, it will be seen that the present invention provides anair quality sampler which not only enables a plurality of gas samples tobe obtained at differing times without operator attendance, but alsoenables the same to be programmed quite readily and simply for varyingthe times during which the samples are taken in different operations.Changes and modifications to the exemplary embodiment described will beapparent to those skilled in the art. It is therefore intended that thecoverage afforded applicant be limited only by the language of theclaims and its equivalent.

We claim:

1. A gas sampler comprising a plurality of gas sample containers; aplurality of generally constant flow pumps. the output of each one ofwhich is communicably connected with an associated one of saidcontainers for respectively directing a quantity of the gas to besampled into each of the containers; and control means connectable withsaid pumps for governing when each of said pumps direects a gas sampleinto its associated container, said control means activating each ofsaid pumps to direct a gas sample into its associated container during adiscrete time interval selected especially for said container andincluding flow rate selection means for determining the rate of flow ofgas into said containers. said flow rate selection means being adaptedto operate each of said pumps intermittently at its generally constantoperating flow rate during the full time interval selected for each ofsaid containers to thereby provide an average flow rate over the fulltime interval which is less than the continuous operating flow rate ofsaid pump while still obtaining a gas sample representative of the gasover said full time interval; and said flow rate selection means beingadjustable to vary the period of said intermittent operation of saidpumping means during the time interval selected for each of saidcontainers and thereby provide a selected one of a plurality ofdiffering average flow rates for said pumping means.

2. A gas sampler comprising a plurality of gas sample containers; aplurality of generally constant flow pumps, the output of each one ofwhich is communicably connected with an associated one of saidcontainers for respectively directing a quantity of the gas to besampled into each of the containers; control means connectable with saidpumps for governing when each of said pumps directs a gas sample intoits associated container. said control means activating each of saidpumps to direct a gas sample into its associated container during adiscrete time interval selected especially for said container andincluding flow rate selection means for determining the rate of flow ofgas into said containers, said flow rate selection means being adaptedto operate each of said pumps intermittently at its generally constantoperating flow rate during the full time interval selected for each ofsaid containers to thereby provide an average flow rate over the fulltime interval which is less than the continuous operating flow rate ofsaid pump while still obtaining a gas sample representative of the gasover said full time interval; and a battery power source for operatingsaid pumps.

3. A gas sampler comprising a plurality of gas sample containers; aplurality of pumps, the output of each one of which is communicablyconnected with an associated one of said containers for respectivelydirecting a quantity-of the gas to be sampled into each of saidcontainers; and control means connectable with said pumps for'activatingeach of said pumps to direct a gas sample into its associated containerduring a discrete time interval selected especially for said container,said control means including programming means permitting the discretetime interval during which said pumping means directs a gas sample intoeach of said containers to be changed, which programming means includesa plurality of control output connections, each one of which isassociated with one of said discrete time intervals and said controlmeans further includes timing means for generating an outputrepresentative of the passage of time, time decoding means for receivingsaid output from said timing means and sequentially activating saidcontrol output connections during the time intervals representedthereby, and means for selectively connecting each of said controloutput connections respectively with a selected pump to provide anenergization signal to said pump for operation thereof to direct a gassample into its associated container during the time intervalrepresented by the control output connection so connected with saidpump.

4. The gas sampler of claim 3 wherein said control means furtherincludes time setting means for synchronizing the sequential activationof said control output connections with an external time source.

5. The gas sampler of claim 3 wherein said timing means of said controlmeans includes an oscillator, a timing processor for receiving theoutput of said oscillator and providing an output representative of hourand minute time divisions, and a memory for holding each of the hourdivisions of said timing processor for the duration of the hourrepresented thereby.

6. The gas sampler of claim 5 further including time display means fordisplaying hour and minute time division from the outputs of said timeprocessor.

7. The gas sampler of claim 3 wherein said time decoding means includesa plurality of dual input gates, the output of each providing arespective one of said control output connections and the inputs theretorepresenting the digits of the hour associated therewith.

8. The gas sampler of claim 3 wherein said pumps are constant flowpumps; and said contol means includes flow rate selection means fordetermining the flow of gas into each respective one of said containersby periodically stopping operation of the pump associated therewithduring the time interval selected for said container, and a plurality ofgates having at least two input terminals, the output terminal of eachrespective one of said gates being connected to the power input of meansfor driving an associated one of said pumps, with one of the inputsbeing connectable to any one of said control output connections, wherebythe output of each of said gates and consequently the operation of thepump associated therewith can only be enabled upon the simultaneousactivation of said means for driving said pump by said flow rateselection means and the control output connection connected therewith.

9. The gas sampler of claim 8 wherein said control means furtherincludes time cycle control means for initiating operation of each ofsaid pumps only during a selected time cycle, and one of said gateinputs is connectable to the output of said time cycle control means toenable initiation of each of said pumps only during a selected timecycle.

10. A gas sampler comprising a plurality of gas sample containers,pumping means for directing a quantity of the gas to be sampled intoeach of said containers, and control means connectable with said pumpingmeans for governing when said pumping means directs a gas sample intoeach of said containers, said control means including programming meanspermitting the selected time interval during which said pumping meansdirects a gas sample into each of said containers to be changed, whichprogramming means includes a plurality of control output connections,each one of which is associated with one of said discrete timeintervals, and said control means further includes timing means forgenerating output representative of the passage of time and timedecoding means for receiving said output from said timing means andsequentially activating said control output connections during the timeintervals represented thereby, and said control means further includingtime cycle control means for initiating operation ofsaid pumping meansduring a selected time cycle and terminating the application of power tosaid pumping means upon completion of a selected time cycle.

1. A gas sampler comprising a plurality of gas sample containers; a plurality of generally constant flow pumps, the output of each one of which is communicably connected with an associated one of said containers for respectively directing a quantity of the gas to be sampled into each of the containers; and control means connectable with said pumps for governing when each of said pumps direects a gas sample into its associated container, said control means activating each of said pumps to direct a gas sample into its associated container during a discrete time interval selected especially for said container and including flow rate selection means for determining the rate of flow of gas into said containers, said flow rate selection means being adapted to operate each of said pumps intermittently at its generally constant operating flow rate during the full time interval selected for each of said containers to thereby provide an average flow rate over the full time interval which is less than the continuous operating flow rate of said pump while still obtaining a gas sample representative of the gas over said full time interval; and said flow rate selection means being adjustable to vary the period of said intermittent operation of said pumping means during the time interval selected for each of said containers and thereby provide a selected one of a plurality of differing average flow rates for said pumping means.
 2. A gas sampler comprising a plurality of gas sample containers; a plurality of generally constant flow pumps, the output of each one of which is communicably connected with an associated one of said containers for respectively directing a quantity of the gas to be sampled into each of tHe containers; control means connectable with said pumps for governing when each of said pumps directs a gas sample into its associated container, said control means activating each of said pumps to direct a gas sample into its associated container during a discrete time interval selected especially for said container and including flow rate selection means for determining the rate of flow of gas into said containers, said flow rate selection means being adapted to operate each of said pumps intermittently at its generally constant operating flow rate during the full time interval selected for each of said containers to thereby provide an average flow rate over the full time interval which is less than the continuous operating flow rate of said pump while still obtaining a gas sample representative of the gas over said full time interval; and a battery power source for operating said pumps.
 3. A gas sampler comprising a plurality of gas sample containers; a plurality of pumps, the output of each one of which is communicably connected with an associated one of said containers for respectively directing a quantity of the gas to be sampled into each of said containers; and control means connectable with said pumps for activating each of said pumps to direct a gas sample into its associated container during a discrete time interval selected especially for said container, said control means including programming means permitting the discrete time interval during which said pumping means directs a gas sample into each of said containers to be changed, which programming means includes a plurality of control output connections, each one of which is associated with one of said discrete time intervals and said control means further includes timing means for generating an output representative of the passage of time, time decoding means for receiving said output from said timing means and sequentially activating said control output connections during the time intervals represented thereby, and means for selectively connecting each of said control output connections respectively with a selected pump to provide an energization signal to said pump for operation thereof to direct a gas sample into its associated container during the time interval represented by the control output connection so connected with said pump.
 4. The gas sampler of claim 3 wherein said control means further includes time setting means for synchronizing the sequential activation of said control output connections with an external time source.
 5. The gas sampler of claim 3 wherein said timing means of said control means includes an oscillator, a timing processor for receiving the output of said oscillator and providing an output representative of hour and minute time divisions, and a memory for holding each of the hour divisions of said timing processor for the duration of the hour represented thereby.
 6. The gas sampler of claim 5 further including time display means for displaying hour and minute time division from the outputs of said time processor.
 7. The gas sampler of claim 3 wherein said time decoding means includes a plurality of dual input gates, the output of each providing a respective one of said control output connections and the inputs thereto representing the digits of the hour associated therewith.
 8. The gas sampler of claim 3 wherein said pumps are constant flow pumps; and said contol means includes flow rate selection means for determining the flow of gas into each respective one of said containers by periodically stopping operation of the pump associated therewith during the time interval selected for said container, and a plurality of gates having at least two input terminals, the output terminal of each respective one of said gates being connected to the power input of means for driving an associated one of said pumps, with one of the inputs being connectable to any one of said control output connections, whereby the output of each of said gates and consequently The operation of the pump associated therewith can only be enabled upon the simultaneous activation of said means for driving said pump by said flow rate selection means and the control output connection connected therewith.
 9. The gas sampler of claim 8 wherein said control means further includes time cycle control means for initiating operation of each of said pumps only during a selected time cycle, and one of said gate inputs is connectable to the output of said time cycle control means to enable initiation of each of said pumps only during a selected time cycle.
 10. A gas sampler comprising a plurality of gas sample containers, pumping means for directing a quantity of the gas to be sampled into each of said containers, and control means connectable with said pumping means for governing when said pumping means directs a gas sample into each of said containers, said control means including programming means permitting the selected time interval during which said pumping means directs a gas sample into each of said containers to be changed, which programming means includes a plurality of control output connections, each one of which is associated with one of said discrete time intervals, and said control means further includes timing means for generating output representative of the passage of time and time decoding means for receiving said output from said timing means and sequentially activating said control output connections during the time intervals represented thereby, and said control means further including time cycle control means for initiating operation of said pumping means during a selected time cycle and terminating the application of power to said pumping means upon completion of a selected time cycle. 